JPS6266974A - Drive circuit - Google Patents

Abstract

PURPOSE:To constitute a simple drive circuit at lower cost wherein a power source is set to one system, by a method wherein, in order to perform voltage control and drive control by the same control signal, a printing head is driven after the boosting of voltage has been stabilized by a first delay means and driving is delayed behined the OFF-time of voltage control by a second delay means t increase a voltage drop speed. CONSTITUTION:Voltage Vh is generated at the output terminal of a booster circuit 10 during printing operation in the OFF-state of a voltage control signal 14 and a printing head 2 is selectively operated by said voltage. When the printing of one line is finished, the voltage control signal 14 comes to an H-level and a diode D1 is turned OFF and the booster circuit 10 begins to raise voltage to Vm. The diode D2 is cut OFF by said voltage control signal 14 and TR1 is turned ON on the basis of a time constant R3.C so as to be delayed by a ton time. When the voltage control signal 14 is cut OFF, voltage drop is started but TR1 is turned OFF on the basis of a time constant R2.C so as to be delayed by a toff time and, therefore, the charge of the load capacitance of the booster circuit is discharged and a voltage drop speed can be increased.

Description

[Detailed Description of the Invention] [Summary] A drive circuit that operates electrical members having different drive periods and drive voltages using the same voltage controllable power supply, the drive circuit comprising: a voltage control signal that boosts the drive voltage of the electrical member; To provide a simple drive circuit that turns on the electrical member by delaying it with a first delay circuit, and turns off the electrical member by delaying it with a second delay circuit when the voltage control signal is turned off to lower the voltage. This has the effect of driving in accordance with the step-up speed of the power supply and increasing the step-down speed.

[Industrial application field]

The present invention relates to improvements in drive circuits.

In devices that drive multiple mechanisms, such as in printers, the driving voltages are often different, and multiple sets of power supplies are required, contributing to increased costs.

However, if the drive period does not overlap with each other, such as print head escape/approach drive and print head drive, it may be possible to perform voltage control and use a single power supply system, but if the power supply is made smaller, the voltage Control responsiveness is poor, and it is necessary to control drive timing relative to voltage control.

Therefore, there is a need for a simple drive circuit that controls the drive timing and uses a single power supply system.

[Conventional technology]

A conventional example will be described below using print head drive and print head escape/approach drive in a thermal printer as examples.

FIG. 3(a) is an explanatory diagram of the escape/approach operation, in which +11 is a front view of the head portion, (2) is a side sectional view, and (3) is an operation time chart.

Thermal printers perform unidirectional printing, as shown in Figure 3(a).
- As shown in (1), the print head 2 approaches the platen l, prints while spacing in the A direction, and when returning, escapes the print head 2 and
Figure (al-(21 of 2") Return to direction B.

The escape/approach operation of the print head 2 is performed by the unidirectional movement of the plunger magnet 4 being held by the holding mechanism 3 and rotationally transmitted, as shown in FIG. 3 +81-+31. The plunger magnet 4 has a driving voltage Vm (about 11V) for a period Tl.
is applied and an escape or approach operation is performed,
The plunger magnet 4 is off during spacing and carriage return.

On the other hand, 24 sets of print heads 2 are provided in the column direction, and the print head drive voltage V is selected based on the print character pattern.
h (7-9V) is applied.

The above two sets of drive circuits are as shown in FIG. 3 (kl).
Voltages Vm and Vh are generated from the battery 9 by booster circuits 5 and 7, respectively, and plunger magnets 4 and 4 are generated by switches 6 and 8, respectively. The print head 2 is driven.

[Problem that the invention seeks to solve]

As explained above, there is a problem in that the cost increases when a booster circuit is provided to generate the drive voltage Vm of the plunger magnet and the drive voltage vh of the print head, respectively.

Since the driving periods of the plunger magnet 4 and the print head 2 do not overlap, it is possible to control the voltage and drive them with one set of booster circuits, but if the booster circuit is made smaller, it will take time to raise and lower the drive. You need to control the timing.

Therefore, an object of the present invention is to provide a simple drive circuit that solves the above problems.

[Means for solving problems]

For the above purpose, the drive circuit of the present invention, as shown in the principle explanatory diagram of FIG. means (11) for boosting the driving voltage of the electric member of the second electric member; and first (12) and second (13) delay means for respectively delaying the rise and fall of the voltage control signal; and means for delaying the voltage control signal by a second delay means to drive the second electric member.

(Function) That is, in order to perform voltage control and drive control using the same control signal, the first delay means (12) performs driving after the voltage boost is stabilized, and the second delay means (13) performs voltage control. This speeds up the step-down speed by delaying the drive compared to when the switch is turned off.

〔Example〕

The details of the present invention will be explained according to the embodiment shown in FIG.

Figure 2 (al is an operation time chart, Figure 2 ('b)
FIG. 2 is a block diagram of a drive circuit according to the present invention.

When the voltage control signal 14 is input to the power supply as shown in FIG. When lowering the voltage as shown in FIG.

The present invention accomplishes the above operations using the same control signal.

In FIG. 2(b), 10 is a booster circuit capable of boosting the battery E to voltages Vm and Vh (Vm>Vh), and a voltage control signal 14 is turned off (
When the voltage control signal 14 is on (L level), the voltage vh is generated by the resistors R1 and R2, and when the voltage control signal 14 is on (H level), the diode Dl is cut off to generate the voltage Vm. TRI is a transistor, and is a power transistor. TR2 is current-driven to drive plunger magnet 4; R3 is to delay the conduction of TRI together with capacitor C and forms a first delay means; R4 is voltage control signal 1;
4, which together with capacitor C form a second delay means when it is off.

Note that the pulse width of the voltage control signal 14 is greater than or equal to the pulse width T1+ton of the drive signal 15.

The operation is as follows.

First, during the printing operation, the voltage control signal 14 is in an off state, the voltage vh is generated as the output of the booster circuit 10, and the print head 2 is selectively operated by this voltage.

When one line of printing is completed, the voltage control signal 14 becomes H level, the diode D1 is turned off, and the booster circuit 10 is set to V
Start pressurizing to m.

This voltage control signal 14 causes the diode D2 to be cut off, and based on the time constant of R3・C, TRI becomes ton.
It turns on after a time delay.

When the voltage control signal 14 turns off (L level), step-down starts, but TRI turns off after a toff time delay due to the time constant R2・C, so that the charge stored in the load capacitance (not shown) of the step-up circuit is reduced. can be released to increase the voltage step-down speed.

As seen in the embodiments described above, it is possible to provide a drive circuit that performs voltage control and uses a single power supply system, and that drives in response to voltage control using a simple delay means.

〔Effect of the invention〕

As described above, the present invention provides a simple drive circuit that uses only one power supply system, and is highly effective in reducing costs in printers and the like.

[Brief explanation of drawings]

Fig. 1 is a diagram explaining the principle of the present invention, Fig. 2 (a) is an operation time chart, Fig. 2 (b) is a block diagram of the drive circuit of the embodiment, and Fig. 3 (a) is the escape/approach of the printer. It is an operation explanatory diagram, (1)
3 is a front view, (2) is a side sectional view, (3) is an operation time chart, and FIG. 3(b) is a conventional drive circuit block diagram. In the figure, 1 is a platen, 2 is a print head, 3 is a holding mechanism, 4 is a plunger magnet, 5 is a Vm booster circuit, 6 and 8 are switches, and 7 is a vh
Booster circuit, 9 is a battery, IO is a power supply, 11 is a voltage control means, 12 is a first delay means, 13 is a second delay means, R1 to R4 are resistors, C is a capacitor, TRI to TR3 are transistors, D1 ~D2 is a diode.

Claims (2)

[Claims] (1) A drive circuit that is connected to a voltage-controllable power supply and drives two sets of electrical members each having a different drive period and drive voltage, the drive circuit being driven by setting the power supply to the drive voltage of the first electrical member. At the same time, the second voltage control signal (14) is input.
means (11) for boosting the drive voltage of the electrical member; and first (12) and second (13) delay means for respectively delaying the rise and fall of the voltage control signal; and means for delaying the voltage control signal by the delay means to drive the second electric member. (2) A set of capacitors is provided, a first delay means for charging the capacitor from the power source via a first resistor when the voltage control signal is on, and a second delay means for charging the capacitor from the power supply when the voltage control signal is off. Claim 1 is characterized in that it is a second delay means for discharging the capacitor via a resistor.
) The drive circuit described in section 2.